Epoxy resin curing agent based on blends containing disecondary aromatic diamines

Abstract

A two component-type curing agent composition is disclosed which comprises a first curing agent which is capable of cross-linking an epoxy resin and which is at least one member selected from primary amines, phenolic compounds and acid anhydrides, and a second curing agent which is at least one compounds represented by the following general formula: ##STR1## wherein X is --CR 1 R 2 --, --CO--, --COO--, --SO 2 --, --SO--, --S--, --O--, --NR 1 --, --SiR 1 R 2 -- or --POR 1 -- where R 1 and R 2 each stands for hydrogen, a lower alkyl or a phenyl; Y and Y' each stands for hydrogen, a lower alkyl or an electron attracting group; R is a lower alkyl; and m and n each is an integer of 1-4.

We claim: 
     
       1. A curing agent composition consisting essentially of a first curing agent which is capable of cross-linking an epoxy resin and which is at least one member selected from the group consisting of aliphatic primary amines, polyamido primary amines, dicyanopolyamides, bisphenols, phenolic resins, vinylphenol polymers and acid anhydrides, and a second curing agent which is at least one compound represented by the following general formula: ##STR16## wherein X is --CR 1  R 2  --, --CO--, --COO--, --SO 2  --, --SO--, --S--, --O--, --NR 1  --, --Sir 1  R 2  -- or --POR 1  -- where R 1  and R 2  each stands for hydrogen, a lower alkyl or a phenyl; Y and Y' each stands for hydrogen, a lower alkyl or an electron attracting group; R is a lower alkyl; and m and n each is an integer of 1-4. 
     
     
       2. A curing agent composition as set forth in claim 1, wherein said first and second curing agents are used in amounts so that said first and second curing agents account for 85 to 5% and 15 to 95%, respectively, of a total of the amounts of active hydrogen of said first and second curing agents. 
     
     
       3. A curing agent composition as set forth in claim 1, wherein said first curing agent is at least one acid anhydride selected from the group consisting of maleic anhydride, succinic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride and methylhexahydrophthalic anhydride. 
     
     
       4. A curing agent composition as set forth in claim 1, wherein said first curing agent is dicyanodiamide or methylhexahydrophthalic anhydride. 
     
     
       5. A curing agent composition as set forth in claim 1, wherein R is an alkyl having 1-3 carbon atoms, X is --CH 2  --, --SO 2  --, --CO--, --O--, --C(CH 3 ) 2  --, --CHC 6  H 5  --, or --CR 1  R 2  -- Y and Y' each is hydrogen, a lower alkyl, a halogen, a nitro group or trifluoromethyl, R 1  and R 2  each is an alkyl having 1-3 carbon atoms, and m and n each is 1 or 2. 
     
     
       6. A curing agent composition as set forth in claim 1 wherein X is --CO--, --COO--, --SO 2  --, --SO--, --S--, --O--, --NR 1  --, --SiR 1  R 2  -- or --POR 1  -- where R 1  and R 2  each stands for hydrogen, a lower alkyl or a phenyl.